Apparatus for the cementing of shoes



June 8, 1943. E. L. CRANDELL 2,321,131

APPARATUS FOR THE CEMENTING OF SHOES Filed May 17, 1941 2 Sheets-Sheet l leave/z Patented June 8, 1943 APPARATUS FOR THE CEMENTING OF SHOES Ervin L. Crandell, Wellesley, Mass., assignor to Compo Shoe Machinery Corporation, Boston, Mass, a corporation oi Delaware Application May 1'7, 1941, Serial No. 393,990

2 Claims.

This invention relates to methods and apparatus for the cementing of shoes and relates more particularly to apparatus for using high frequency electric energy for heating adhesive for cementing shoe parts together.

The Pitman Patent No. 2,087,480 and the Smith Patent No. 2,109,323 disclose the cementing of shoe bodies to outsoles through the use of heat derived from high frequency electrostatic fields. Each of said patents discloses the use of a pair 01' electrodes connected to opposite sides of a high frequency electrical source for generating heat in heat responsive adhesives, one electrode being placed within the shoe, on one side of the adhesive, and the other being placed at the bottom of the outsole.

With some types of shoes when pairs of 0pposed electrodes as disclosed in said Pitman and Smith patents, are used, the shanks and toreparts of the shoes are heated unevenly. The

construcion of one particular shoe may be such that the shank will get hotter than the forepart where both receive energy from a common source. In another shoe the forepart may get hotter than the shank where both receive energy from a common source. It is desirable therefore for avoiding overheating in one part of a shoe and perhaps underheating in another part of the shoe to be able to regulate the heat at the shank and at the forepart separately.

This invention provides for the regulation of the heat at the shank and forepart of a shoe, separately by adjustment of the intensity of the electrostatic field at the shank and at the forepart separately.

into two sections, one at the iorepart and one at the shank of a shoe with the two sections connected separately to the high frequency electric source so that the electric energy to each may be separately controlled for providing exactly the desired degree of heat at the shank and at the forepart.

An object of the invention is to improve the quality of cemented shoes.

Another and more definite object of the invention is to provide difierent degrees of heat at the shank and at the forepart of a shoe being cemerited.

The invention will now be described with refercnce to the drawings, of which:

Fig. 1 is a side elevation of a shoe press containing a shoe assembly and embodying this invention;

Fig. 2 is a plan view with'a portion of its cover I In one embodiment oi the invention one of the opposed electrodes is separated removed, of an electrode pad containing inter laced electrodes which may be used in the practice of this invention;

Fig. 3 is a circuit schematic showing three electrodes which may be used in the practice of the invention, one of the electrodes being capacity coupled to the other electrodes;

Fig. 4 is a circuit schematic showing three electrodes which may be used in the practice of the invention, together with means for varying the electric energy supplied to two of the electrodes;

Fig. 5 is a sectional view of a lasted shoe and the relations of the forepart and the shank of the shoe to separate electrodes, one of which is placed under the shank and the other under the forepart of the shoe, and

Fig. 6 is a diagrammatic view illustrating the .interlaced electrodes of Fig. 2 connected to a high frequency electric source.

In sole cementing utilizing electrostatic fields, it is the practice as disclosed in said Smith patent, to roughen the bottom of the lasted shoe and the top of the outsole; to coat these parts with an adhesive such as is disclosed in said Pitman patent; to apply pressure to the parts by inflating the pad, and then to expose the shoe to heat derived from an electrostatic field.

The shoe press I of Fig. .1 includes the inflatable pad ll into which a fluid may be introduced for applying pressure to a shoe assembly as disclosed in detail in said Smith patent. The press In is substantially a duplicate of that of Fig. l of said Smith patent except that in the present press, provision is made for the electric supply to three electrodes instead of to the two electrodes in the patent.

The electric conducting bolt l3 makes contact through the conducting plate H, the conducting lining l 5, and the conducting pin IS, with an electrode l1 within the shoe assembly. This electrode I! may be a metal bottom on the last I8 or it may be an electrode built onto the shoe body as disclosed in my copending application, Serial N51,: $87,823. The bolt [3 is grounded to the press a The electrode pad ill of Fig. I placed between the inflatable pad H and the outsole 20 contains electrodes arranged as disclosed by Figs. 4 and 5, there being two lower electrodes 22 and 23, the electrode 22 being below the forepart of the shoe and the electrode 23 being below the shank of the shoe. The pad I 9 may have upper and lower enclosing portions of soft leather or or rubber, with their edges suitably fastened as by stitching or by cementing.

The vacuum tube triode 24 of Fig. 4 has its anode 25 connected through a radio frequency choke 26 to a suitable high voltage source of direct current. The anode 25 is connected through the blocking condenser 21 to one end of the tank coil 28, the other end of the tank coil being connected to the cathode 29 of the tube 24 and to ground. The grid circuit of the tube contains the coil 3|) which is connected in series with the grid 3| of the tube, and with the leak 32 and condenser 33 in shunt, and with the cathode 29. The constants of the coils determine the frequency at which the tube 24 oscillates. The frequency of 20 megacycles being, for example, suitable.

The upper electrode I1 is connected to ground as illustrated by Figs. 1, 4 and 5. The forepart electrode 22 which, for example, may be wire mesh, is connected through the lead 63, the radio frequency ammeter 34, and the variable condenser 35 to the tap 36 on the tank coil 28.

The shank electrode 23 is connected through the lead 31, the radio frequency ammeter 38, and the condenser 39 to the tap 40 on the coil 28.

The variable condensers 35 and 39 serve for varying the high frequency voltage applied separately to the forepart and shank electrodes and the meters 34 and 38 serve for indicating the current flow in each circuit. Since the capacitive reactance in the circuits remains substantially constant, the current flow is proportional to the applied voltage.

The condensers 35 and 39 act due to the high frequency in the same way as variable resistors do in direct current circuits, to reduce the voltage and the current flowing in the separate circuits thus giving individual control of the heat in the shank and the forepart of the shoe.

In the embodiments of Figs. 2 and 6, all electrodes-are arranged on the same side of the work, that is at the under side of the outsole of the shoe. The electrodes of these figures are prei' erably in the form of fiat plates which are interlaced as illustrated.

The forepart electrodes 4| of Figs. 2 and 6 are connected together and by the lead 42 and the variable condenser 43 to the tap 44 on the tank coil 28.

The shank electrodes 45 are connected together and by the lead 46 and the variable condenser 41 to the tap 48 on the tank coil 28.

The electrodes 49 are connected together and by the lead 50 to the ground side of the tank coil 28.

A field would be set up between the electrodes 4| and 49 and between the electrodes 45 and 49, which field would extend into the work area to produce heat in the adhesive between the outsole and the shoe. The condensers 43 and 41 may be adjusted as described in the foregoing to vary the heat separately in the shank and forepart areas.

In the embodiment of Fig. 3, the two opposed electrodes 5| and 52 are connected to opposite sides of the tank coil circuit while the free electrode 53 spaced from the electrodes 5| and 52 is capacitively coupled thereto, and an electro static field between'the free electrodes and the other direct connected electrodes is set up, the intensity of which field depends upon the capacity between the respective electrodes which in turn depends upon their physical dimensions and spacing. A stronger field would of course, be produced between the direct connected electrodes 5| and 52 than between either and the free electrode.

Either of the electrodes 52 or 53 could be placed above or below the shank or forepart of the shoe depending upon the peculiarities of an individual shoe.

While embodiments of the invention have been described for the purpose of illustration, it should be understood that the invention is not limited to the exact apparatus and arrangements of apparatus illustrated as modifications thereof may be suggested by those skilled in the art without departure from the essence of the invention.

What is claimed is:

1. Shoe cementing apparatus comprising a shoe press including means for pressing an outsole against a shoe with an adhesive therebetween; an electrode pad upon said means and adapted to be pressed by said means against the outsole of a shoe; a first electrode in said pad in the fore part area of the shoe; a second electrode in said pad in the shank area of the shoe, spaced from said first electrode; a third electrode in said pad having portions in both of said areas; said portions being spaced from said first and second electrodes; means for producing high frequency electrostatic fields between said third electrode and said first electrode and between said third electrode and said second electrode, and means for adjusting independently the strength of said fields.

2. Shoe cementing apparatus comprising a shoe press including means for pressing an outsole against a shoe with an adhesive therebetween; an electrode pad upon said means and adapted to be pressed by said means against the outsole of a shoe; 3. first electrode in said pad in the fore part area of the shoe; a second electrode in said pad in the shank area of the shoe, spaced from said first electrode; a third electrode in said pad having portions in both of said areas; said portions being spaced from said first and second electrodes; means for producing high frequency electrostatic fields between said third electrode and said first electrode and between said third electrode and said second electrode, said first and second electrodes having portions interlaced with said portions of said third electrode, and means for adjusting independently the strength of said fields.

ERVIN L. CRANDELL. 

